108 lines
2.7 KiB
C
108 lines
2.7 KiB
C
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/*
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* tinfgzip - tiny gzip decompressor
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*
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* Copyright (c) 2003 by Joergen Ibsen / Jibz
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* All Rights Reserved
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*
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* http://www.ibsensoftware.com/
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*
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* Copyright (c) 2014-2016 by Paul Sokolovsky
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*
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* This software is provided 'as-is', without any express
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* or implied warranty. In no event will the authors be
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* held liable for any damages arising from the use of
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* this software.
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*
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* Permission is granted to anyone to use this software
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* for any purpose, including commercial applications,
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* and to alter it and redistribute it freely, subject to
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* the following restrictions:
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*
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* 1. The origin of this software must not be
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* misrepresented; you must not claim that you
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* wrote the original software. If you use this
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* software in a product, an acknowledgment in
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* the product documentation would be appreciated
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* but is not required.
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*
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* 2. Altered source versions must be plainly marked
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* as such, and must not be misrepresented as
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* being the original software.
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*
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* 3. This notice may not be removed or altered from
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* any source distribution.
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*/
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#include "tinf.h"
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#define FTEXT 1
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#define FHCRC 2
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#define FEXTRA 4
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#define FNAME 8
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#define FCOMMENT 16
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void tinf_skip_bytes(TINF_DATA *d, int num)
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{
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while (num--) uzlib_get_byte(d);
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}
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uint16_t tinf_get_uint16(TINF_DATA *d)
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{
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unsigned int v = uzlib_get_byte(d);
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v = (uzlib_get_byte(d) << 8) | v;
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return v;
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}
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int uzlib_gzip_parse_header(TINF_DATA *d)
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{
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unsigned char flg;
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/* -- check format -- */
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/* check id bytes */
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if (uzlib_get_byte(d) != 0x1f || uzlib_get_byte(d) != 0x8b) return TINF_DATA_ERROR;
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/* check method is deflate */
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if (uzlib_get_byte(d) != 8) return TINF_DATA_ERROR;
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/* get flag byte */
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flg = uzlib_get_byte(d);
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/* check that reserved bits are zero */
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if (flg & 0xe0) return TINF_DATA_ERROR;
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/* -- find start of compressed data -- */
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/* skip rest of base header of 10 bytes */
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tinf_skip_bytes(d, 6);
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/* skip extra data if present */
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if (flg & FEXTRA)
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{
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unsigned int xlen = tinf_get_uint16(d);
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tinf_skip_bytes(d, xlen);
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}
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/* skip file name if present */
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if (flg & FNAME) { while (uzlib_get_byte(d)); }
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/* skip file comment if present */
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if (flg & FCOMMENT) { while (uzlib_get_byte(d)); }
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/* check header crc if present */
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if (flg & FHCRC)
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{
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/*unsigned int hcrc =*/ tinf_get_uint16(d);
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// TODO: Check!
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// if (hcrc != (tinf_crc32(src, start - src) & 0x0000ffff))
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// return TINF_DATA_ERROR;
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}
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/* initialize for crc32 checksum */
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d->checksum_type = TINF_CHKSUM_CRC;
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d->checksum = ~0;
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return TINF_OK;
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}
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